Methods are provided for making use of an apparatus for generating vibrational energy in a borehole, the apparatus utilizes a mass and a rotary source for suspending the mass in a borehole or in casing in a borehole or in an instrument housing that may be positioned in an opened or cased borehole arranged to cause frictional contact with the surface of the rotating mass, the mass being rotatable about is rotational axis in one direction to cause it to backward whirl in the opposite direction, the centrifugal force of the whirling mass serving to generate vibrational energy that is used to obtain geophysical information as to the structure of the earth surrounding and adjacent to the borehole and for enhancing cementing and production enhancing techniques in oil or gas wells.
A downhole seismic energy source for use in generating a seismic signal in a borehole including an elongated mass having a generally cylindrical surface of diameter less than the borehole, an actuator suspending the cylindrical mass in the borehole wherein the cylindrical surface thereof is in frictional contact with the borehole wall, the cylindrical mass being rotatable about its rotational axis to cause the mass to whirl within the borehole in the direction opposite the direction of the rotation of the mass, the mass cylindrical force serving to create a seismic energy signal.